The present invention relates generally to buckle assemblies for use with safety seat belts and, more particularly, to such buckle assemblies which disengage automatically after a time delay in the event of a collision.
Since front seat safety lap belts became standard equipment on all American-made automobiles in 1964, a significant portion of the public has been resistant to using such safety belts In recognition of the relatively low rate of utilization of seat belts, and considering the savings in lives and money which result from the use of seat belts, legislation has, at various times, been proposed in which alternative safety restraints, such as air bags, would be required as standard equipment in automobiles. The principle idea behind such proposals has been that of providing vehicles with safety restraint systems which operate independently of the voluntary cooperation of the driver or occupant. Unfortunately, such systems, particularly air bags, are considerably more expensive to implement than conventional seat belts.
Many people refrain from using seat belts out of fear that they will become trapped by the belts in the event of a collision and be unable to escape from the vehicle if unnecessary. Consequently, it has been proposed that seat belts be designed so as to release automatically after a certain time delay following a collision. Various designs for such automatically releasing seat belts have been proposed using a variety of mechanical, electrical and hydraulic release and timing mechanisms.
One of the most promising concepts for providing the time delay feature of an automatically-releasing safety belt is the use of a hydraulic fluid flowing under pressure through a restriction as the primary timing means. Typically, this involves a dashpot-type device with either a fixed orifice or one that can be adjusted by means of a needle valve.
The principle problem with the use of hydraulic flow control mechanisms using an orifice as a means of mechanical restriction is that they are severly affected by the presence of contaminants introduced during the manufacturing process, unless very elaborate means are provided, such as clean room conditions with accompanying precautions, which is costly and time consuming. It would be desirable to provide an automatically-releasing safety belt using a controlled flow hydraulic mechanism as the timing element which can be produced at relatively low cost and which is free from failure caused by contaminants introduced into the mechanism either during manufacture or later during field use.